Vehicle Flow Monitoring System

ABSTRACT

A vehicle flow monitoring system for detecting both a car count and direction of movement of vehicles passing a point of interest. The vehicle flow monitoring system generally includes a car counter which may include a microcontroller and a pair of distance sensors. Each of the distance sensors is oriented toward a unique point of interest. Each of the distance sensors includes a threshold distance reading which is used to detect whether a vehicle has passed underneath the car counter. The system may determine direction of travel of the vehicle based on which of the distance sensors is passed by the vehicle first. The microcontroller may assign an Event ID to each time a vehicle passes each of the sensors, with the Event ID being used to identify when and if the vehicle should be counted, or whether a non-vehicle object has passed the car counter.

CROSS REFERENCE TO RELATED APPLICATIONS

Not applicable to this application.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable to this application.

BACKGROUND Field

Example embodiments in general relate to a vehicle flow monitoringsystem for detecting both a car count and direction of movement ofvehicles passing a point of interest.

Related Art

Any discussion of the related art throughout the specification should inno way be considered as an admission that such related art is widelyknown or forms part of common general knowledge in the field.

Detecting and counting a vehicle as it passes a point for the purposesof determining parking lot usage, statistics or analysis has been aroundfor some time, with traditional means of detection including ‘roadtubes’, infra-red, magnetometer, image processing and inductive loops.

‘Road tubes’ are tubes installed on the road surface that trigger achange in pressure when an axle travels over the tube, which is thendetected and counted. However, it only detects axles and therefore isdifficult to distinguish between tail gating vehicles and trucks andsimilar such circumstances.

Inductive loops are impractical to install and are unreliable. They areoften used for entry and exit points on parking lots and due to theirunreliability, quickly lead to cumulative errors. Also, to determine thedirection of a vehicle, two loops are required—doubling the impracticalissues of installation.

Image processing is complicated and therefore prone to errors. Althoughthe image sensor does not require mounting on the road surface,increasing the reliability, it is highly susceptible to difficult tocontrol environmental conditions such as lighting.

Magnetometer based vehicle detection sensors typically measuredisruptions in the earth's magnetic field caused by the presence of avehicle. This disruption is small and unpredictable, as well as beingtemperature dependent—for these reasons, magnetometer based sensors havenever achieved a high level of detection accuracy. These are alsotypically mounted on the road surface, which creates reliability issuesdue to the harsh environment.

Infra-red sensors rely heavily upon a clear or translucent windowthrough an enclosure. This enclosure window is easily prone to damagerendering the sensor useless. When the window is blocked, eitherdeliberately by misguided youths for example, or through environmentaleffects such as snow, the detection does not work. Furthermore, infraredsensors typically only have a binary output of present or not, limitingtheir practical use in algorithms.

SUMMARY

An example embodiment is directed to a vehicle flow monitoring system.The vehicle flow monitoring system includes a car counter which mayinclude a microcontroller and a pair of distance sensors. Each of thedistance sensors is oriented toward a unique point of interest. Each ofthe distance sensors includes a threshold distance reading which is usedto detect whether a vehicle has passed underneath the car counter. Thesystem may determine direction of travel of the vehicle based on whichof the distance sensors is passed by the vehicle first. Themicrocontroller may assign an Event ID to each time a vehicle passeseach of the sensors, with the Event ID being used to identify when andif the vehicle should be counted, or whether a non-vehicle object haspassed the car counter.

There has thus been outlined, rather broadly, some of the embodiments ofthe vehicle flow monitoring system in order that the detaileddescription thereof may be better understood, and in order that thepresent contribution to the art may be better appreciated. There areadditional embodiments of the vehicle flow monitoring system that willbe described hereinafter and that will form the subject matter of theclaims appended hereto. In this respect, before explaining at least oneembodiment of the vehicle flow monitoring system in detail, it is to beunderstood that the vehicle flow monitoring system is not limited in itsapplication to the details of construction or to the arrangements of thecomponents set forth in the following description or illustrated in thedrawings. The vehicle flow monitoring system is capable of otherembodiments and of being practiced and carried out in various ways.Also, it is to be understood that the phraseology and terminologyemployed herein are for the purpose of the description and should not beregarded as limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

Example embodiments will become more fully understood from the detaileddescription given herein below and the accompanying drawings, whereinlike elements are represented by like reference characters, which aregiven by way of illustration only and thus are not limitative of theexample embodiments herein.

FIG. 1A is a side view of a vehicle flow monitoring system having oneunobstructed distance sensor in accordance with an example embodiment.

FIG. 1B is a side view of a vehicle flow monitoring system having avehicle passing underneath a distance sensor in accordance with anexample embodiment.

FIG. 2 is a perspective view of a vehicle flow monitoring system inaccordance with an example embodiment.

FIG. 3A is a side view of a vehicle flow monitoring system having twounobstructed distances sensors in accordance with an example embodiment.

FIG. 3B is a side view of a vehicle flow monitoring system having avehicle passing underneath a pair of distance sensors in accordance withan example embodiment.

FIG. 4 is a perspective view of a vehicle flow monitoring system inaccordance with an example embodiment.

FIG. 5A is a side view of a vehicle flow monitoring system having a pairof diagonally-oriented distance sensors in accordance with an exampleembodiment.

FIG. 5B is a side view of a vehicle passing underneath a pair ofdiagonally-oriented distance sensors of a vehicle flow monitoring systemin accordance with an example embodiment.

FIG. 6 is a perspective view of a vehicle flow monitoring system inaccordance with an example embodiment.

FIG. 7 is a top view of a vehicle flow monitoring system in use tomonitor two lanes of traffic in accordance with an example embodiment.

FIG. 8 is a perspective view of a vehicle flow monitoring system inaccordance with an example embodiment.

FIG. 9 is a side view of a vehicle flow monitoring system in use inaccordance with an example embodiment.

FIG. 10 is a perspective view of a vehicle flow monitoring system inaccordance with an example embodiment.

FIG. 11 is a graph illustrating various Event ID's of a vehicle flowmonitoring system in accordance with an example embodiment.

FIG. 12 is a block diagram of a vehicle flow monitoring system inaccordance with an example embodiment.

FIG. 13 is a flowchart illustrating operation of a vehicle flowmonitoring system in accordance with an example embodiment.

FIG. 14 is a flowchart illustrating detection of a vehicle underneath acar counter of a vehicle flow monitoring system in accordance with anexample embodiment.

FIG. 15 is a flowchart illustrating passage of a vehicle past a carcounter of a vehicle flow monitoring system in accordance with anexample embodiment.

FIG. 16 is a flowchart illustrating passage of a person past a seconddistance sensor of a vehicle flow monitoring system in accordance withan example embodiment.

FIG. 17 is a flowchart illustrating passage of a person past a firstdistance sensor of a vehicle flow monitoring system in accordance withan example embodiment.

FIG. 18 is a flowchart illustrating passage of a vehicle and trailerpast a car counter of a vehicle flow monitoring system in accordancewith an example embodiment.

FIG. 19 is a flowchart illustrating detection of a tailgate or trailerscenario of a vehicle flow monitoring system in accordance with anexample embodiment.

DETAILED DESCRIPTION A. Overview

An example vehicle flow monitoring system generally comprises a carcounter 20 which is adapted to detect passage of a vehicle 12, whereinthe car counter 20 comprises a first distance sensor 21 and a seconddistance sensor 22. The first distance sensor 21 may be oriented towardsa first point of interest and the second distance sensor 22 may beoriented towards a second point of interest. The first distance sensor21 is adapted to detect each of the vehicles 12 passing the firstdistance sensor 21. The second distance sensor 22 is adapted to detecteach of the vehicles passing the second distance sensor 22. The firstpoint of interest is distally-spaced with respect to the second point ofinterest.

A microcontroller 24 is communicatively interconnected with the carcounter 20, wherein the microcontroller 24 is communicativelyinterconnected with a database 31, wherein the database includes a firstthreshold value for the first distance sensor 21 and a second thresholdvalue for the second distance sensor 22, wherein the microcontroller 24is adapted to detect when a first distance reading detected by the firstdistance sensor 21 is greater than or less than the first thresholdvalue, wherein the microcontroller is adapted to detect when a seconddistance reading detected by the second distance sensor 22 is greater orless than the second threshold value; wherein the microcontroller 24 isadapted to count each vehicle 12 passing the car counter 20.

The microcontroller 24 may be adapted to detect direction of movement ofthe vehicle 12 based on which of the first distance sensor 21 or thesecond distance sensor 22 is passed by the vehicle 12 first. The firstdistance sensor 21 and the second distance sensor 22 may each becomprised of a LIDAR sensor. The first threshold value may be configuredto be beyond a noise level of an unobstructed distance reading of thefirst distance sensor 21. The second threshold value may be configuredto be beyond a noise level of an unobstructed distance reading of thesecond distance sensor 22.

The car counter 20 may be positioned above the first and second pointsof interest. The distance between the points of interest may be shorterthan a length of the vehicle 12. The first distance sensor 21 may bedistally-spaced with respect to the second distance sensor 22, whereinboth the first distance sensor 21 and the second distance sensor 22 arevertically-oriented. Alternatively, the first distance sensor 21 may beadjacent to the second distance sensor 22, wherein both the firstdistance sensor 21 and the second distances sensor 22 are bothdiagonally-oriented towards their respective points of interest.

The first and second distance sensors 21, 22 may be adapted to takedistance measurements at the same time. The first threshold value of thefirst distance sensor 21 may be calibrated based on noise readings fromthe first distance sensor 21 and the second threshold value of thesecond distance sensor 22 may be calibrated based on noise readings fromthe second distance sensor 22.

The microcontroller 24 may be directly connected to both of the distancesensors 21, 22. The microcontroller 24 may be adapted to classifytransitions from unobstructed measurements to obstructed measurements byeach of the first distance sensor 21 and the second distance sensor 22as an event. The microcontroller 24 may be adapted to assign an Event IDto each of the events detected by the distance sensors 21, 22. Themicrocontroller 24 may be adapted to recognize when a non-vehicle objecthas passed the first distance sensor 21 or the second distance sensor 22such that the non-vehicle object is not counted. The microcontroller 24may also be adapted to identify when the vehicle has a trailer based ona sequence of Event ID's. The microcontroller 24 may be adapted to resetthe distance sensors 21, 22 after a period of time has passed.

In an example embodiment, the car counter 20 may comprise a thirddistance sensor 28 and a fourth distance sensor 29, wherein the firstand second distance sensors 21, 22 monitor a first lane of traffic andwherein the third and fourth distance sensors 28, 29 monitor a secondlane of traffic.

B. Car Counters

As shown throughout the figures, the vehicle flow monitoring system 10may include car counters 20 for monitoring the flow of vehicles past adesired location. By way of example, the desired location could be anentrance or exit to a parking garage, which will allow monitoring of thenumber of available parking spaces. As another non-limiting example, thedesired location could be a roadway on which it is desired to analyzetraffic patterns, such as is typical when analyzing whether a roadwayneeds to be improved to accommodate different traffic patterns.

The figures illustrate a number of exemplary embodiments of car counters20 for use with the vehicle flow monitoring system 10. It should beappreciated that the illustration and description of such exemplaryembodiments is for exemplary purposes only, and thus should not beconstrued as limiting in scope. For example, the number, positioning,and orientation of any distance sensors 21, 22, 27, 28 may vary indifferent embodiments.

In the exemplary embodiment shown in FIGS. 1A, 1B, and 2, only a firstdistance sensor 21 is utilized. As shown in FIG. 1A, the first distancesensor 21 may be positioned above the point of interest to be monitoredfor vehicle flow. For example, in a parking garage, the distance sensor21 may be secured to the ceiling of the parking garage. As anotherexample, on an uncovered roadway, the distance sensor 21 could besuspended or otherwise secured above the roadway, such as by a supportsuch as a pole as is commonly used for lighting on roadways. As yetanother example, the distance sensor 21 could be secured to the sameframework as traffic lights.

As shown in FIG. 1A, the distance sensor 21 continuously takes adistance reading between the distance sensor 21 and a point underneaththe distance sensor 21. When no vehicle 12 is underneath the distancesensor 21, the distance sensor 21 will detect the distance to theroadway such as shown in FIG. 1A.

When a vehicle 12 is underneath the distance sensor 21, the distancesensor 21 will detect the distance to the vehicle such as shown in FIG.1B. In this manner, the distance sensor 21 can determine whether avehicle 12 is passing underneath the distance sensor 21, as the distancebetween the distance sensor 21 and the roadway will be greater than thedistance between the distance sensor 21 and the vehicle 12 when thevehicle is passing underneath.

FIG. 2 illustrates usage of a car counter 20 comprised of a singledistance sensor 21 in use in a parking garage 14. As can be seen, asingle distance sensor 21 has been positioned over a lane of the parkinggarage 14. The positioning of the distance sensor 21 may vary indifferent embodiments. For example, the distance sensor 21 could bepositioned on an entry lane of the parking garage 14 so as to count thenumber of vehicles 12 entering the parking garage 14. A separatedistance sensor 21 could be positioned on an exit lane of the parkinggarage 14 so as to count the number of vehicles 12 exiting the parkinggarage 14. In this manner, the number of vehicles 12 within the parkinggarage 14 can be monitored.

As the vehicle 12 is moving within the lane being monitored by the carcounter 20, the timing of the distance sensor 21 will dictate if thesensor 21 detects a “hit” on a vehicle 12 passing underneath the sensor21. Therefore, the sampling rate of the distance sensor 21 will affectreadings. For example, the more frequently readings are taken, the morelikely a vehicle 12 passing underneath the distance sensor 21 willresult in a shorter distance detected by the distance sensor 21.

By way of example and without limitation, an exemplary embodiment mayutilize distance samples taken at 50 times per second (50 Hertz).However, the sampling rate for distance measurements could vary withinany range capable of being processed by a requisite processing device,such as a microcontroller 24 as discussed herein. The sampling rate ofthe distance sensor 21 could be adjusted to suit variousimplementations. For example, in areas with slower traffic (such aswithin a parking garage), a sampling rate of 20 Hz may be suitable. Inareas with faster traffic (such as over a roadway), a sampling rate of100 Hz may be more desirable to ensure accurate readings.

FIGS. 1A, 1B, and 2 illustrate an exemplary position of the firstdistance sensor 21 over the point of interest. However, it should beappreciated that the positioning of the first distance sensor 21 mayvary in different embodiments. The systems and methods described hereinare flexible with respect to the mounting position of the distancesensor 21, and any configuration can be supported so long as a vehicle12 in the path of the distance sensor 21 yields a different reading thanwhen a vehicle 12 is not present. By way of example and withoutlimitation, in some embodiments the distance sensor 21 may be positionedhorizontally across the path of the vehicle 12, vertically underneaththe vehicle such as on the road surface, or any angle therebetween.

While use of a car counter 20 comprising a single distance sensor 21provides some car counting functionality, it should be understood that asingle distance sensor 21 is not operable to determine the direction oftravel of the vehicle 12. In situations in which direction of movementis to be detected, it would be beneficial to add a second distancesensor 22 such that readings from both distance sensors 21, 22 may beutilized to determine the direction of travel of the vehicle 12.

For example, it may be desirable to only count vehicle's 12 going in acertain direction. With the use of a second distance sensor 22 asdiscussed below, vehicles 12 travelling in an opposite direction can beexcluded from the count. The use of a second distance sensor 22 may alsoreduce errors introduced from random events such as pedestrians passingby the distance sensor 21 in one-sensor embodiments.

FIGS. 3A, 3B, and 4 illustrate a first exemplary embodiment of a carcounter 20 utilizing a pair of distance sensors 21, 22. In such anexemplary embodiment, it can be seen that a microcontroller 24 may bepositioned between the distance sensors 21. It should be appreciatedthat the use of a hard-wired microcontroller 24 is optional. Forexample, in some embodiments, the distance sensors 21, 22 may bewirelessly connected to the microcontroller 24, such as through acommunications protocol such as Bluetooth. In such wireless embodiments,the microcontroller 24 may be positioned remotely with respect to thedistance sensors 21, 22. For example, in the case of a parking garage, asingle microcontroller 24 could be positioned in a housing and adaptedto remotely communicate with any sensors 21, 22 in the parking garage.

The exemplary embodiment of FIGS. 3A, 3B, and 4 illustrates amicrocontroller 24 which is positioned on the overheard ceiling of aparking garage adjacent to the pair of distance sensors 21, 22. Whilethe figure illustrates that the microcontroller 24 is centrally-locatedbetween the distance sensors 21, 22, it should be appreciated that suchpositioning of the microcontroller 24 is merely for illustrativepurposes, as the microcontroller 24 may be positioned at variouslocations with respect to the distance sensors 21, 22 including, in someembodiments, remotely.

By use of two sensors 21, 22 such as shown in FIGS. 3A, 3B, and 4, thedirection of travel of the vehicle 12 may be determined by the carcounter 20. With this type of arrangement, the first distance sensor 21may detect a shorter distance than the second distance sensor 22 as thecar passes underneath. This enables the detection of the direction ofthe vehicle.

As a vehicle 12 passes underneath the car counter 20, it is desirablethat neither of the distance sensors 21, 22 read the maximum distancereading to the point of interest such as the road surface while avehicle 12 is passing the point of interest. In this manner, falsepositives can be avoided. Thus, the spacing of the distance sensors 21,22 with respect to each other should be limited to less than theexpected length of the longest vehicle 12 expected to pass under the carcounter 20.

This distance may vary depending on the location of the car counter 20.For example, in a parking garage with limited clearance, it is extremelyunlikely that a large semi-truck would be passing under the car counter20. In such an embodiment, the distance between the distance sensors 21,22 may be minimized since a longer vehicle 12 is not expected. Bycontrast, a car counter 20 positioned over a freeway will necessarilyneed to have the distance sensors 21, 22 spaced appropriately for longervehicles such as semi-trucks.

The pair of distance sensors 21, 22 may be centrally-located above thepoint of interest such as shown in the figures, with each of thedistance sensors 21, 22 being equidistance from the point of interest.For example, if the first distance sensor 21 is two meters away from thepoint of interest in a first horizontal direction, the second distancesensor 22 may be two meters from the point of interest in a secondhorizontal direction. These sample distances are merely exemplary andshould not be construed as limiting in scope, as the spacing between thedistance sensors 21, 22 will be determined based on the expected lengthof the vehicles 12 being monitored.

The sampling of distance readings from the distance sensors 21, 22 alsoneed to be timed properly to ensure accurate readings. In a preferredembodiment, each of the pair of distance sensors 21, 22 samples distancereadings within the same time window, such as at the same point in time.However, due to constraints in processing power, available sensors 21,22, and communications protocols, the measurements taken by each of thedistance sensors 21, 22 may be slightly separated in time. However, thereadings will still be accurate so long as the readings are as far apartin time as the time it would take for the vehicle 12 to travel thedistance from the first distance sensor 21 to the second distance sensor22.

The manner in which the two-sensor car counter 20 operates to both countcars and determine direction of travel may vary in differentembodiments. In a simplified methodology, a vehicle 12 will be countedeach time that both distance sensors 21, 22 detect a distance less thanthat to the point of interest (the road surface). When both distancesensors 21, 22 revert to detecting the distance to the point ofinterest, the car count for that vehicle 12 will be completed and thesystem will be reset awaiting another vehicle 12. If only a singledistance sensor 21 is triggered at a time, it can be often assumed thatit was not a vehicle 12 that passed underneath the distance sensors 21,22. If both distance sensors 21, 22 are triggered, it can be assumedthat a vehicle 12 passed underneath the distance sensor 21, 22.

The first distance sensor 21, 22 to trigger will indicate the directionof travel of the vehicle 12. For example, if the first distance sensor21, 22 triggers first, the vehicle 12 is moving in the direction of thefirst distance sensor 21. If the second distance sensor 21, 22 triggersfirst, the vehicle 12 is moving in the direction of the second distancesensor 22. In this manner, the direction of movement of the vehicle 12may be determined through the usage of the two distance sensors 21, 22.

In the exemplary embodiment shown in FIGS. 1-4, it can be seen that eachillustrated distance sensor 21, 22 is oriented vertically to point downtoward the road surface, forming a right angle with the ceiling or othersurface to which the distance sensor 21, 22 is secured. In an alternateembodiment as shown in FIGS. 5A, 5B, and 6, it can be seen that thedistance sensors 21, 22 are instead angularly-oriented in a diagonalorientation. Such an embodiment may be utilized to save space as the twodistance sensors 21, 22 may be positioned directly adjacent to eachother. In such an embodiment, the microcontroller 24 may be positionedabove the distance sensors 24 with a wired connection or remotely with awireless connection.

FIGS. 7 and 8 illustrate an embodiment of a car counter 20 in which fourdistance sensors 21, 22, 28, 29 are utilized. In such an embodiment, afirst pair of distance sensors 21, 22 comprised of a first distancesensor 21 and a second distance sensor 22 may be positioned over a firstlane on the first side of a lane divider 18 and a second pair ofdistance sensors 28, 29 comprised of a third distance sensor 28 and afourth distance sensor 29 may be positioned over a second lane on thesecond side of a lane divider 18.

In this manner, two adjacent lanes of traffic may be simultaneouslymonitored, with the first lane of traffic being monitored by the firstpair of distance sensors 21, 22 and the second lane of traffic beingmonitored by the second pair of distance sensors 28, 29. The distancesensors 21, 22, 28, 29 may be positioned adjacent to each other andoriented diagonally such as shown in the figures to form an X-pattern.In other embodiments, a microcontroller 24 may be centrally-located witheach other the distance sensors 21, 22, 28, 29 being connected to themicrocontroller 24. The distance sensors 21, 22, 28, 29 may also bevertically-oriented in such an embodiment though not shown in thefigures.

In some embodiments, it may be possible to detect direction of travelwith use of a single distance sensor 21, provided that the singledistance sensor 21 could be positioned to take readings where desired.In other words, the distance sensor 21 may be movable along a surface,such as through the use of rails, tracks, or the like. So long as thedistance sensor 21 is configured to move at an appropriate speed, itcould perform the function of a pair of sensors 21, 22 by moving withthe vehicle 12. It should also be appreciated that, in situations withlong vehicles being expected, additional sensors 21, 22, 28, 29 could beutilized for each lane. For example, rather than the use of two sensors21, 22 per lane, an embodiment with longer vehicles expected could usethree, four, five, or more sensors 21, 22, 28, 29 per lane.

It should be appreciated that a wide range of different types ofdistance sensors 21, 22, 28, 29 may be utilized in differentembodiments. By way of example and without limitation, the distancesensors 21, 22, 28, 29 could rely on a wide range of signals, includingbut not limited to laser, infrared LED, sonic waves, and the like. Assuch, it should be appreciated that both light-based (visual) andsound-based (sonic) sensors may be utilized for different embodiments.

In a preferred embodiment as shown in FIG. 9, the preferred distancesensor 21, 22, 28, 29 used for providing distance readings in the carcounter 20 is a LIDAR (light detection and ranging) sensor. A LIDARsensor is typically an integrated instrument that fires rapid pulses oflaser light in the oriented direction and then detects any of the pulsesthat are reflected back to the LIDAR sensor. The time of flight for thereflected pulses is recorded. The distance to the reflecting object (inmost cases, a road surface) can then be determined, such as by themicrocontroller 24. The microcontroller 24 may be integrated orinterfaced with the LIDAR sensor(s). Although LIDAR sensors arepreferred for traffic monitoring, it should be appreciated that othertypes of sensors or distance measuring methods may be utilized.

C. Vehicle Monitoring Algorithm

A car counting algorithm is utilized to process the distancemeasurements from the distance sensors 21, 22, 28, 29 so as to determinevehicle 12 count and direction of travel. The distance sensors 21, 22,28, 29 are first calibrated. After calibration, analysis and readingsmay be performed.

During the calibration phase, the car counter 20 is calibrated for itsspecific installation. For example, different locations will necessarilyhave a different distance between the distance sensors 21, 22, 28, 29and the point of interest such as a road or ground surface. Calibrationis utilized to fine-tune each sensor 21, 22, 28, 29 to its specificlocation and orientation.

Calibration is used to determine what should be considered an“unobstructed” distance reading and what types of readings should beconsidered to trigger a car count. For example, two values for use in asimple calibration would be (1) the distance to the point of interestwhen unobstructed and (2) a minimum distance to be considered sufficientto trigger a car count.

Mounting heights, locations, and angles of orientation of the distancesensors 21, 22, 28, 29 may vary depending on the surroundings. Further,not all vehicles have an identical profile and height. In fact, anysystem should accommodate for a wide range of vehicle 12 types. Onemethod of calibration utilizes manual entry of data for a fixedcalibration. In such a fixed calibration, the physical unobstructeddistance from each distance sensor 21, 22, 28, 29 to the point ofinterest (generally a ground surface) may be manually measured andentered into the system.

However, such a fixed calibration may suffer from shortcomings, such asfalse readings due to different vehicle 12 types. Thus, it is beneficialto utilize a dynamic calibration algorithm that dynamically calculates adistance that is considered the threshold of unobstructed or obstructedreadings. Further, as each distance sensor 21, 22, 28, 29 used tomonitor a single point of interest may be installed with differentgeometry, it is important that the calibration (whether fixed ordynamic) be performed for each of the distance sensors 21, 22, 28, 29 ofany particular car counter 20.

During normal operation, the measured unobstructed distance from adistance sensor 21 will remain substantially constant with anyvariations being attributable to small errors in the distancemeasurement. If the distance measurement is obstructed for one reason oranother, this may result in a larger variation over a data set. Usingthese principles, calibration may be set. Taking data over a set timewindow (such as 30 seconds, but in some embodiments may be more orless), if the variation of data is measured and considered acceptable,the distance data can be averaged and the result considered to be theunobstructed distance for that distance sensor 21. A threshold distancefor an obstruction can then be set as an offset from the calculatedunobstructed distance average, with the threshold being set beyond thebounds of the variation in readings to eliminate noise.

Given the dynamic nature of various locations in which the car counter20 may be set, it is often desirable to use a dynamic calibration. Insuch an embodiment, the calibration is repeated continuously duringoperation. For example, each set time window (period) with acceptablevariation is used to calculate a new average and offset. There willoften be stretches of time (off-peak hours) where there are noobstructions, such as when no vehicles 12 are passing under the carcounter 20. The dynamic calibration accounts for such unobstructedperiods of time.

With the car counter 20 being calibrated to correlate distance sensor 21readings, including unobstructed distance measurements and offsetthresholds beyond which are to be considered a vehicle, an algorithm maybe utilized to detect if a vehicle 12 has passed the point of interest.The systems and methods described herein may use the assignment ofnumbers to each event, with each event representing that the thresholdhas been crossed for a given distance sensor 21, 22, 28, 29 of the carcounter 20.

The summing of these events in comparison to known pattern sums combinedwith some state tracking can then be made for the determination ofwhether an object should be counted. The numbers may be assigned suchthat the summing of numbers will always be unique. By way of example andwithout limitation, one such method for ensuring unique numbers is useof Binary (base 2) format for assigned event numbers.

With reference to FIG. 9, an exemplary car counter 20 is shown which iscomprised of a first distance sensor 21, a second distance sensor 22,and a microcontroller 24. The distance sensors 21, 22 are illustrated ascomprising LIDAR sensors, though other types of sensors may be utilizedas discussed previously.

In such an embodiment, the microcontroller 24 will utilize four eventsto determine if a vehicle has passed. If these events are numbered withan index starting at zero, then using Base 2 format with the indexnumber as the personal notation (bit position) in binary format, theevent numbers will be 2⁰=1, 2¹=2, 2²=4, 2³=8. The events of significanceare thus split up as follows.

Event ID 2⁰=1 represents the first distance sensor 21 going from abovethreshold to below threshold (first distance sensor 21 down).

Event ID 2¹=2 represents the first distance sensor 21 going from belowthreshold to above threshold (first distance sensor 21 up).

Event ID 2²=4 represents the second distance sensor 22 going from abovethreshold to below threshold (second distance sensor 22 up).

Event ID 2³=8 represents the second distance sensor 22 going from belowthreshold to above threshold (second distance sensor 22 up).

The event identification numbers are not, by themselves, sufficient toaccurately determine if a vehicle 12 has passed the position of interestand the direction of travel. However, the combination of consecutiveevents does allow such determinations to be made. Thus, as events arecontinuously occurring, they are stored in a buffer for further analysis(such as by the microcontroller 24).

Continuing to reference FIG. 9, it can be seen that a vehicle 12 haspassed the second distance sensor 22 but not yet reached the firstdistance sensor 21. At this point in time, the second distance sensor's22 readings have gone from above threshold to below threshold, resultingin the event carrying a value of 4, which is placed in the event buffer.Moments later when the vehicle 12 moves in the direction indicated topass under the first distance sensor 21, an event with the value of 1,representing the first distance sensor 21 going from above threshold tobelow threshold, will be triggered and stored in the buffer.

When two consecutive events sum up to equal 5, it can be considered thatthe vehicle is over the position of interest. This event value will workregardless of the direction of travel of the vehicle 12. The vehicle 12direction of travel may also be determined by examining which eventoccurred first. For reliability, it is prudent that the order of eventsoccurring while the vehicle moves over the position of interestcorrespond to those of the vehicle leaving the point of interest.

At this point, there are two events in the buffer (4, 1) and themicrocontroller 24 knows that they have summed to 5 and thus there iscurrently a vehicle over the position of interest. The microcontroller24 can then anticipate that the next readings should correspond to thevehicle 12 leaving. The following two events added to the buffer wouldideally then be 8 as the rear of the vehicle 12 moves out fromunderneath the second distance sensor 22, followed by 2. The buffer thusholds the event values (4, 1, 8, 2) at this point. Two consecutiveevents summing to equal ten may thus indicate that a vehicle 12 has leftthe position of interest.

As described above, the use of event numbers assigned to variousreadings for each distance sensor 21, 22, 28, 29 can be used todetermine both (1) whether a vehicle 12 is underneath the car counter 20and (2) the direction of travel of the vehicle 12. While the aboveexample used only a pair of distance sensors 21, 22, it should beappreciated that additional distance sensors 21, 22 may also beaccommodated in such a system to accommodate longer vehicles. Further,the values using Base 2 format is merely for exemplary purposes, andother number values may be utilized in different embodiments.

To prevent or limit errors, the microcontroller 24 will only consider avehicle 12 leaving the point of interest if the vehicle 12 has beendeemed to have arrived over the point of interest and the order ofevents for leaving correlates correctly with the vehicle 12 arriving. Ifso, a vehicle 12 count may be added or subtracted to/from the system asdesired based on direction. FIG. 11 illustrates a graph showing thesequence of events just described above for a single vehicle 12 passingunder the distance sensors 21, 22.

The car counter 20 is configured to prevent or minimize occurrences offalse positives, such as due to a small obstruction passing under thecar counter 20. For example, in a parking garage, individuals willfrequently pass under the car counter 20 while walking to or from theirvehicles 12. It is important that the car counter 20 not register suchindividuals as vehicles 12 so as to ensure an accurate count.

The algorithm discussed above prevents false positives due to smallobstructions such as individuals passing underneath the car counter 20.In such a situation, the first distance sensor 21 would go both up anddown before any triggering of the second distance sensor 22. If a personwere to walk under the car counter 20, the first distance sensor 21would read event ID's as a 1 followed by a 2, resulting in a sum of 3for the first distance sensor 21. The second distance sensor 22 wouldread event ID's as a 4 followed by an 8, resulting in a sum of 12 forthe second distance sensor 21. Therefore, if the microcontroller 24detects the sum of consecutive events as equaling 3 or 12, themicrocontroller 24 will not consider the event to represent a vehicle 12and it will not be counted.

The described algorithm may also be utilized to prevent false positivesdue to a pair of close vehicles 12 (e.g., one vehicle 12 tailgatinganother) or a vehicle 12 towing a trailer. In such a situation, it ispossible that the second distance sensor 22 would trigger an event ID of4 shortly after an event ID of 8, prior to the leading vehicle 12passing completely from underneath the first distance sensor 21. Such asituation may occur if a second vehicle 12 or a trailer was closer tothe first vehicle 12 than the distance separating the distance sensors21, 22. The second event ID of 4 would then be followed by an event IDof 1 as the tailing vehicle 12 or trailer passes under the firstdistance sensor 21. Then, as the tailing vehicle moves forward, thesecond distance sensor 22 would trigger an event ID of 8 and then thefirst distance sensor 21 would trigger an event ID of 2 to provide atotal event ID sequence of (4, 1, 8, 4, 2, 1, 8, 2).

The algorithm may accommodate for such situations by examining the sumof three consecutive event ID's in situations in which a vehicle 12arrival has been detected previously. For example, such a situation mayoccur when two consecutive event ID's sum to 5. If a tailgating scenariois occurring, the sum of three consecutive event ID's will be equal to13 or 7. In the above scenario, it can be seen that three consecutiveevent ID's sum to 7 (4, 2, 1) indicating a tailgating scenario.

The system may treat such tailgating scenarios differently depending onthe situation. One possible treatment of such scenarios is for thesystem to count the capture of the tailgating scenario as an additionalvehicle 12. This approach may be desirable when counting vehicles 12entering a parking garage 14 since a vehicle 12 towing a trailer or atailgating vehicle 12 will occupy two parking spaces 15. In anotherscenario, such as on a high-speed freeway, it would more likely that thevehicle 12 has a trailer rather than a tailgater due to the relativespeed of vehicles 12 travelling. In such a situation, an additionalcount may not be added.

In either case, the event buffer is cleared up to the point of theoriginal arrival after the appropriate event sequence has been detectedand flagged. In an embodiment utilizing a pair of distance sensors 21,22, the event buffer will always be removed of four events. After thealgorithm has removed any such tailgating events, the system will resetto the same state as if a single vehicle 12 is passing. In other words,the system will be in a state that a vehicle 12 has arrived and awaitingdeparture with the corresponding exit pattern having event ID's summedto ten, representing event ID's of (8, 2) which represents the vehicle12 passing. A single vehicle 12 will be counted.

The algorithm may also accommodate for variance and errors in readings.For example, a vehicle 12 moving at speed with an irregular shape mayresult in two consecutive matching sets of events occurring. Forexample, the event buffer would be (1, 2, 1, 2) or (8, 4, 8, 4). In suchcircumstances, the system will be configured to ignore duplicate sets ofevents. For example, if the system reads (1, 2, 1, 2), the system willignore the duplicate set and instead output only (1, 2). Similarly, ifthe system reads (8, 4, 8, 4), the system will ignore the duplicate setand instead output only (8, 4). In this manner, such false positives canbe accommodated for in real-time without affecting future events.

The system will generally reset or resolve an event buffer when bothdistance sensors 21, 22 return readings above their detection thresholdas there is no vehicle or obstruction under either of the sensors 21,22. Any flags remaining in the buffer can also be cleared. Further, thesystem may be configured to remove events after a certain period of timehas passed. FIG. 13 illustrates an exemplary flowchart showing operationof the algorithm with a car counter 20 including two distance sensors21, 22.

D. Vehicle Flow Monitoring System

The systems and methods described above may be incorporated into alarger vehicle flow monitoring system 10 configured to provide trafficand/or parking statistics and/or guidance based on the data receivedfrom the car counter(s) 20 and other devices described below.

FIG. 12 illustrates an exemplary vehicle flow monitoring system 10 whichincorporates a central control unit 30, a database 31, car counters 20,parking sensors 26, a user interface 37, vehicles 12, dynamic signage34, mobile devices 35, and guidance lights 36. As shown in FIG. 12, thecar counters 20 communicate to a cloud-based central control unit 30either directly or through a communications network such as a gateway.

The central control unit 30 may be a single computer system or may bemultiple computer systems through distributed computing. The centralcontrol unit 30 may be comprised of a server computer or a standaloneprocessing box. The central control unit 30 may include a database 31 ormay be communicatively interconnected with a database 31. The centralcontrol unit 30 may be interconnected with the car counters 20 and otherdevices via a wired connection or a wireless connection, such as Wi-Fi,RF, Bluetooth, or the like.

The central control unit 30 may either include or be communicativelyinterconnected with a database 31. In either case, the associateddatabase 31 may contain all relevant data for the vehicle flowmonitoring system 10. By way of example and without limitation, thedatabase 31 may include data such as device locations, device counts,parking structure details, users, login information, historical cartransitions, details of associated dynamic signage, operationalparameters and the like along with the association of all data elements.The database 31 may be stored across multiple systems or may be storedon a single system.

The central control unit 30 may display a user interface 37 which may beused by operators of the vehicle flow monitoring system 10 to ensurethat all elements of the system 10 are properly functioning. Forexample, the user interface 37 may indicate if one or more sensors 21,22, 26, 28, 29 have failed. As another example, the user interface 37may provide data related to calibration. As yet another example, theuser interface 37 may display the readings of the car counters 20 and/orparking sensors 26. The user interface 37 may be visible directly on thecentral control unit 30, or may be visible remotely such as through theuse of a mobile device 35.

Continuing to reference FIG. 12, it can be seen that parking sensors 26may be communicatively interconnected with the central control unit 30.As shown in FIG. 10, an exemplary parking garage 14 includes a pluralityof parking spaces 15 defined by lines on the underlying road surface. Inan exemplary embodiment, each of the parking spaces 15 may include itsown parking sensor 26. In other embodiments, only some of the parkingspaces 15 may include a parking sensor 26.

Each of the parking spaces 15 is communicatively interconnected with thecontrol unit 30. The parking sensors 26 may be comprised of varioustypes of sensors known in the art to indicate whether an object such asa vehicle 12 is parked in the parking space 15. In an exemplaryembodiment, each parking sensor 26 is adapted to indicate to the centralcontrol unit 30 whether the associated parking space 15 is occupied orunoccupied.

As shown in FIG. 12, the vehicle flow monitoring system 10 may alsoinclude dynamic signage 34. The signage 34 may provide relevantinformation processed by the control unit 30. For example, in a parkinggarage 14, the signage 34 may indicate the number of available parkingspaces 15 which is detected by use of the parking sensors 26. In aparking garage 14 without parking sensors 26, the car counter 20 mayinstead by utilized to provide the number of available parking spaces 15to be displayed on the signage 34.

Continuing to reference FIG. 12, it can be seen that mobile devices 35may be communicatively interconnected with the control unit 30. Themobile devices 35 may comprise smart phones, smart watches, laptops, andthe like. The mobile devices 35 may provide various functionality, suchas but not limited to displaying a user interface 37 which may be usedfor displaying data from the vehicle flow monitoring system 10. Forexample, the user interface 37 on the mobile device 35 may display thenumber of parking spaces 15 which are available in a parking garage 14.As another example, the user interface 37 on the mobile device 35 maydisplay traffic patterns on a desired roadway.

The vehicle flow monitoring system 10 may also include guidance lights36 which will guide vehicles 12 based on information from the carcounters 20 and/or parking sensors 26. For example, the guidance lights36 may illuminate to guide a vehicle 12 toward parking spaces 15 thatare known to be available due to the parking sensors 26. It should beappreciated that the guidance lights 36 may provide a wide range offunctionality.

E. Operation of Preferred Embodiment

FIGS. 14 and 15 illustrate an exemplary method of counting a vehicle 12passing a point of interest. In the exemplary situation shown in FIGS.14 and 15, a vehicle 12 passes the second distance sensor 22 of the carcounter 20 first. As the front of the vehicle 12 passes the seconddistance sensor 22, the second distance sensor's 22 distance readingwill go from above to below the threshold. An Event ID of 4 will thus beentered into the buffer. As the front of the vehicle 12 passes the firstdistance sensor 21, the first sensor's 21 distance reading will go fromabove to below threshold. An Event ID of 1 will be entered in thebuffer.

At this point, the sum of the two most recent events is equal to 5, sothe control unit 30 will recognize that a vehicle 12 is underneath thecar counter 20. The control unit 30 will also know the direction oftravel of the vehicle 12 based on the second distance sensor 22 being“triggered” first.

As shown in FIG. 15, as the rear of the vehicle 12 passes the seconddistance sensor 22, the second distance sensor's 22 distance readingwill go from below to above the threshold. An Event ID of 8 will beentered into the buffer. As the rear of the vehicle 12 passes the firstdistance sensor 21, the first distance sensor's 21 distance reading willgo from below to above threshold. An Event ID of 2 will be entered inthe buffer.

At this point, the sum of the two most recent events is equal to 10, sothe control unit 30 will recognize that the vehicle 12 has left the carcounter 20. The control unit 30 will then update the database 31 toreflect the additional vehicle 12 having been counted by updating thecar count.

FIGS. 16 and 17 illustrate an exemplary method of recognizing that ahuman, rather than a vehicle 12, has passed the car counter 20. As theperson passes the second distance sensor 22, the second distance sensor22 will go from above to below threshold and a 4 will be entered in thebuffer. Because the first distance sensor 21 will generally bedistally-spaced with respect to the second distance sensor 22, thesecond distance sensor 22 will also detect the person leaving fromunderneath the second distance sensor 22, resulting in the seconddistance sensor 22 going from below to above threshold prior to theperson reaching the first distance sensor 21. An Event ID of 8 will beentered in the buffer.

As the sum of the most recent events is 12, the control unit 30 willrecognize that it was not a vehicle 12 that passed under the car counter20. No car count will be added to the database 31. FIG. 17 illustratesthe same method being used in connection with the first distance sensor21, which results in Event ID's of (1, 2) which sum to 3 and aresimilarly recognized by the control unit 30 as a non-vehicle passage.

FIGS. 18 and 19 illustrate an exemplary method of recognizing atailgating situation in which either two vehicles 12 are drivingdangerously close to each other or a single vehicle 12 has a trailer orother towed apparatus. As the front of the vehicle 12 passes the seconddistance sensor 22, an Event ID of 4 is entered into the buffer. As thefront of the vehicle 12 passes the first distance sensor 21, an Event IDof 1 is entered in the buffer. As the rear of the vehicle 12 passes thesecond distance sensor 22, an Event ID of 8 is entered in the buffer.

If the vehicle 12 is towing a trailer, the front of the trailer willthen pass the second distance sensor 22, resulting in an Event ID of 4being entered into the buffer. The rear of the vehicle 12 will next passthe first distance sensor 21, resulting in an Event ID of 2 entered inthe buffer. The front of the trailer will then pass the first distancesensor 21, resulting in an Event ID of 1 entered in the buffer. The rearof the trailer will then pass the second distance sensor 22, resultingin an Event ID of 8 entered in the buffer. Finally, the rear of thetrailer will pass the first distance sensor 21, resulting in an Event IDof 2 being entered in the buffer.

After both the vehicle 12 and trailer have passed the car counter 20,the Event buffer will read (4, 1, 8, 4, 2, 1, 8, 2) as outlined above.The control unit 30 will recognize that the sum of three consecutiveevents (1, 8, 4) is equal to 13, which is representative of a tailgatingscenario. The control unit 30 may choose to add only a single car countin such a circumstance or, in some embodiments, may still add a doublecar count to accommodate for the extra parking space 15 taken by thetrailer.

It should be appreciated that the vehicle flow monitoring system 10 maybe utilized in a wide range of settings to provide a wide range offunctionality. The control unit 30 will generally collate data fromvarious sensors such as car counters 20 and/or parking sensors 26 to bestored in the database 31 for appropriate system applications.

For example, car counters 20 may be arranged on a roadway such as afreeway to monitor traffic patterns and loads during different times.This data may be continuously stored in the database 31 to be retrievedwhen needed. As an example, using this information, traffic engineerscan make plans to improve such roadways based on data received andprocessed by the vehicle flow monitoring system 10.

As another example, if a parking garage 14 or parking lot with fortyspaces has a single entry and exit point, a car counter 20 may bepositioned at both the entry and the exit along with dynamic signage 34displaying parking availability. As a vehicle 12 enters the parkinggarage 14, the car counter 20 will recognize the vehicle's 12 entry andcommunicate an updated car count to the control unit 30. The controlunit 30 then updates the database 31 and revises the available number ofparking spaces 15, which is displayed on the dynamic signage 34.

Similarly, when a vehicle 12 exits the parking garage 14, the carcounter 20 will recognize the vehicle's 12 exit and communicate anupdated car count to the control unit 30. The control unit 30 thenupdates the database 31 to reflect the exited vehicle 12 and revises theavailable number of parking spaces 15, which is updated on the dynamicsignage 34.

Because the system recognizes vehicle 12 direction of movement, avehicle 12 entering the parking garage 14 through the exit lane willstill be counted as an added car count rather than a subtraction, sincethe system 10 will recognize that the vehicle 12 entered, rather thanexited, the parking garage 14 based on the detected direction ofmovement of the vehicle 12.

In some embodiments, a parking garage 14 or lot may form part of aseries of parking areas which are associated with the same complex, suchas a hospital or shopping mall. Each of the parking areas may includetheir own car counters 20 and/or parking sensors 26 so that the dynamicsignage 34 and database 31 may be updated with car counts for both theentire complex and for individual parking areas such as parking garages14. The system 10 is fully configurable using the control unit 30. Forexample, the system 10 may be configured to use guidance lights 36 todirect motorists to the parking area in the complex with the mostavailable parking spaces 15.

As yet another non-limiting example, a car counter 20 may be placed atall entry and exit points for an area of interest such as a centralbusiness district of a city. The control unit 30 may then determine thetotal number of vehicles within the central business district andcommunicate that information to dynamic signage 34 or store the relevantinformation for viewing and analysis via a user interface 37.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Although methods and materialssimilar to or equivalent to those described herein can be used in thepractice or testing of the vehicle flow monitoring system, suitablemethods and materials are described above. All publications, patentapplications, patents, and other references mentioned herein areincorporated by reference in their entirety to the extent allowed byapplicable law and regulations. The vehicle flow monitoring system maybe embodied in other specific forms without departing from the spirit oressential attributes thereof, and it is therefore desired that thepresent embodiment be considered in all respects as illustrative and notrestrictive. Any headings utilized within the description are forconvenience only and have no legal or limiting effect.

1. A vehicle flow monitoring system, comprising: a car counterconfigured to detect passage of a vehicle, wherein the car countercomprises a first distance sensor and a second distance sensor; whereinthe first distance sensor is oriented towards a first point of interest,wherein the first distance sensor is configured to detect the vehiclepassing the first distance sensor; wherein the second distance sensor isoriented towards a second point of interest, wherein the second distancesensor is configured to detect the vehicle passing the second distancesensor, wherein the first point of interest is distally-spaced withrespect to the second point of interest; and a microcontrollercommunicatively interconnected with the car counter, wherein themicrocontroller is communicatively interconnected with a database,wherein the database includes a first threshold value for the firstdistance sensor and a second threshold value for the second distancesensor, wherein the microcontroller is configured to detect when a firstdistance reading detected by the first distance sensor is greater thanor less than the first threshold value, wherein the microcontroller isconfigured to detect when a second distance reading detected by thesecond distance sensor is greater or less than the second thresholdvalue; wherein the microcontroller is configured to increase a vehiclecount when the first distance reading is less than the first thresholdvalue and the second distance reading is less than the second thresholdvalue.
 2. The vehicle flow monitoring system of claim 1, wherein themicrocontroller is configured to detect direction of movement of thevehicle based on which of the first distance sensor or the seconddistance sensor is passed by the vehicle first.
 3. The vehicle flowmonitoring system of claim 1, wherein the first distance sensor and thesecond distance sensor are each comprised of a LIDAR sensor.
 4. Thevehicle flow monitoring system of claim 1, wherein the first thresholdvalue is configured to be beyond a noise level of an unobstructeddistance reading of the first distance sensor.
 5. The vehicle flowmonitoring system of claim 4, wherein the second threshold value isconfigured to be beyond a noise level of an unobstructed distancereading of the second distance sensor.
 6. The vehicle flow monitoringsystem of claim 1, wherein the car counter is positioned above the firstpoint of interest and the second point of interest.
 7. The vehicle flowmonitoring system of claim 1, wherein the first distance sensor isdistally-spaced with respect to the second distance sensor, wherein boththe first distance sensor and the second distance sensor arevertically-oriented.
 8. The vehicle flow monitoring system of claim 1,wherein the first distance sensor is adjacent with respect to the seconddistance sensor, wherein both the first distance sensor and the seconddistance sensor are diagonally-oriented.
 9. The vehicle flow monitoringsystem of claim 1, wherein the car counter comprises a third distancesensor and a fourth distance sensor, wherein the first distance sensorand the second distance sensor monitor a first lane of traffic, whereinthe third distance sensor and the fourth distance sensor monitor asecond lane of traffic.
 10. The vehicle flow monitoring system of claim1, wherein a distance between the first point of interest and the secondpoint of interest is shorter than a length of the vehicle.
 11. Thevehicle flow monitoring system of claim 1, wherein the first distancesensor and the second distance sensor are configured to take distancemeasurements simultaneously.
 12. The vehicle flow monitoring system ofclaim 1, wherein the first threshold value of the first distance sensoris calibrated based on noise readings from the first distance sensor andthe second threshold value of the second distance sensor is calibratedbased on noise readings from the second distance sensor.
 13. The vehicleflow monitoring system of claim 1, wherein the microcontroller isdirectly connected to both the first distance sensor and the seconddistance sensor.
 14. The vehicle flow monitoring system of claim 1,wherein the microcontroller is configured to classify transitions fromunobstructed measurements to obstructed measurements by each of thefirst distance sensor and the second distance sensor as an event. 15.The vehicle flow monitoring system of claim 14, wherein themicrocontroller is configured to assign an Event ID to the eventdetected by the first distance sensor and the second distance sensor.16. The vehicle flow monitoring system of claim 15, wherein themicrocontroller is configured to recognize when a non-vehicle object haspassed the first distance sensor or the second distance sensor such thatthe non-vehicle object is not counted.
 17. The vehicle flow monitoringsystem of claim 15, wherein the microcontroller is configured toidentify when the vehicle has a trailer based on a sequence of EventID's.
 18. The vehicle flow monitoring system of claim 1, wherein themicrocontroller is configured to reset the first distance sensor and thesecond distance sensor after a period of time has passed.
 19. A vehicleflow monitoring system, comprising: a car counter configured to detectpassage of a vehicle into or out of a parking area, wherein the parkingarea comprises a plurality of parking spaces, wherein the parking areacomprises a dynamic signage, wherein the car counter comprises a firstdistance sensor and a second distance sensor; wherein the first distancesensor is oriented towards a first point of interest, wherein the firstdistance sensor is configured to detect vehicle passing the firstdistance sensor; wherein the second distance sensor is oriented towardsa second point of interest, wherein the second distance sensor isconfigured to detect the vehicle passing the second distance sensor,wherein the first point of interest is distally-spaced with respect tothe second point of interest; and a microcontroller communicativelyinterconnected with the car counter, wherein the microcontroller iscommunicatively interconnected with a database, wherein the databaseincludes a first threshold value for the first distance sensor and asecond threshold value for the second distance sensor, wherein themicrocontroller is configured to detect when a first distance readingdetected by the first distance sensor is greater than or less than thefirst threshold value, wherein the microcontroller is configured todetect when a second distance reading detected by the second distancesensor is greater or less than the second threshold value; wherein themicrocontroller is configured to increase a vehicle count when the firstdistance reading is less than the first threshold value and the seconddistance reading is less than the second threshold value; wherein thedynamic signage is configured to display the vehicle count.
 20. Thevehicle flow monitoring system of claim 19, wherein the dynamic signageis configured to display a number of the plurality of parking spaces ofthe parking area which are available.
 21. A vehicle flow monitoringsystem, comprising: a car counter configured to detect passage of avehicle, wherein the car counter comprises a first distance sensor and asecond distance sensor; wherein the first distance sensor is orientedtowards a first point of interest, wherein the first distance sensor isconfigured to detect the vehicle passing the first distance sensor;wherein the second distance sensor is oriented towards a second point ofinterest, wherein the second distance sensor is configured to detect thevehicle passing the second distance sensor, wherein the first point ofinterest is distally-spaced with respect to the second point ofinterest; and a microcontroller communicatively interconnected with thecar counter, wherein the microcontroller is communicativelyinterconnected with a database, wherein the database includes a firstthreshold value for the first distance sensor and a second thresholdvalue for the second distance sensor, wherein the microcontroller isconfigured to detect when a first distance reading detected by the firstdistance sensor is less than the first threshold value, wherein themicrocontroller is configured to detect when a second distance readingdetected by the second distance sensor is less than the second thresholdvalue; wherein the microcontroller is configured to increase a vehiclecount when the first distance reading is less than the first thresholdvalue and the second distance reading is less than the second thresholdvalue.